Gas turbines such as are offered by the applicant, for example under, inter alia, the type designation GT13E2, are operated with an annular combustion chamber. The combustion itself may occur using premixer burners (referred to below for short as burners) such as are described, for example, in EP A1 321 809 or AP A1 704 657, wherein these documents and the developments which have been made therefrom are an integrated component of this application, and are incorporated by reference herein. Such an annular combustion chamber is described, for example, in DE A1 196 44 378, which annular combustion chamber is reproduced in certain details in FIG. 1 of this application. The gas turbine 10 which is illustrated in FIG. 1 of this application has a turbine casing 11 which surrounds a plenum 14 which is filled with compressed combustion air in the region of the combustion chamber 15. The annular combustion chamber 15, which merges with a hot gas duct 22, is arranged concentrically around the central rotor 12 in the plenum 14. The space of the combustion chamber 15 is bounded on the inside by an inner shell 21′ and on the outside by an outer shell 21. The inner shell 21′ and outer shell 21 are each divided in a separating plane into an upper part and a lower part. The upper part and lower part of the inner shell 21′ and outer shell 21 are connected in the separating plane in such a way that an annular space is formed which conducts the hot gas generated by the burners 16 to the rotor blades 13 of the turbine. The separating plane is convenient when assembling and disassembling the machine. The combustion chamber 15 itself is lined with special wall segments 17.
The inner shell 21′ and outer shell 21 are cooled convectively in the described embodiment. Here, cooling air, which enters the plenum 14 after exiting the compressor as compressed air stream 23, mainly flows in the opposite direction of flow to that of the hot gas in the hot gas duct 22. The cooling air then flows on from the plenum 14 through an outer cooling duct 20 and inner cooling duct 20′, which cooling ducts are formed by cooling jackets 19, 19′ which surround the shells 21, 21′ at a distance. The cooling air then flows along the shells 21, 21′ in the cooling ducts 20, 20′, in the direction of the combustion chamber dome 18 which surrounds the combustion chamber 15. At said combustion chamber dome 18, the air is then available to the burners 16 as combustion air.
The hot gas flows from the burners to the turbine and in doing so flows along the hot-gas-side surfaces of the inner shell 21′ and outer shell 21. The pressure loss which is available for cooling is predefined by the thermodynamic process peripheral conditions. A rise in the pressure drop has an adverse effect on the efficiency of the gas turbine. An efficient manner of cooling in the case of locally high heat transfer coefficients is impingement cooling, in which the cooling medium impinges vertically, in the form of jets, on the surface which is to be cooled. The effect of the impingement cooling (medium heat transfer coefficient) in an existing impingement cooling plate is, however, attenuated by a transverse flow of cooling air in the direction of the cooling duct.